Goal:
The goal of this project is to develop more durable, longer-lasting drill bits.

Background:
This project builds on a previous project (DE-FC26-97FT34366) that demonstrated the feasibility of forming diamond composite structures with tungsten carbide during the process of sintering (densifying) the tungsten carbide. The tungsten carbide developed proved to be 30% stronger than conventionally processed tungsten carbide with significantly less brittle performance characteristics. This follow-on effort will investigate the feasibility of adding other composite metal materials to the process with the ultimate goal of manufacturing an entire drill bit in a single microwave process. Specifically, this project will: 1) develop an efficient and economically viable microwave processing technique to process composites of cobalt (Co) cemented tungsten carbide (WC) and diamond; 2) develop a compositionally graded system with steel and WC/Co as two end phases; and, 3) develop hard metal (WC/Co), diamond and steel composites in an encapsulated system (a complete drill bit) using microwave technology.

Performers:
Pennsylvania State University
Dennis Tool Company

Location:
University Park, Pennsylvania 16802

Project Impact:
This study has advanced our understanding of an improved methodology for producing microwave sintered drill components that exhibit superior properties to those that have been conventionally manufactured. A special microwave oven has been successfully produced and is being marketed by Dennis Tool Company of Houston, Texas.

Comparison Of Conventionally And Microwave Sintered Wc-Co Drill Parts

Accomplishments:
PSU has tested a variety of microwave-processed parts to determine their strength relative to conventionally produced parts. These tests have shown the following project accomplishments:

20-30% increase in wear performance

Three to four times more resistant to cobalt leaching by acid treatment

Current Status and Remaining Tasks:
The results of exploratory research to develop diamond composites with WC/Co as the matrix have been highly encouraging. PSU researchers are using nickel, titanium and chromium-coated diamond powders because pure diamond powder is sensitive to Co attack and does not form a bond with the matrix. PSU has successfully obtained about 96% density of the diamond composites at ambient pressure without damaging the diamond.

PSU has transferred the prototype microwave system to an industrial partner, Dennis Tool Company, to manufacture the technology and an agreement has been established with Valenite, a leading producer of cutting and drilling tools and wear parts, to market the technology. This project is complete and a final report has been submitted.